Excessive B cell activity and effects in regulatory T cell funmction occur in patients with active SLE; these abnormalities are less marked when the disease is quiescent. Nevertheless, excessive b cell proliferation occurs even in inactive patients. Studies with monoclonal anti-T cell antibodies indicate that many patients have abnormal presence of activated T cells and increased numbers of B cells. Study of a large number of patients with SLE indicate that SLE is not a disease, but a syndrome with different cellular bases.